1. Field of the Invention
The present invention relates generally to tube liners for pipes and systems and methods for the manufacture of tube liners, and more particularly to cured-in-place tube liners.
2. Description of the Related Art
Much of the infrastructure in cities around the world was installed many years ago, and is now beginning to age and decay. For example, aging pipes for sewers, storm drains, water, gas, oil, etc. begin to leak due to cracks/damage in the walls of the pipes and in connection between pipe segments. Where the pipe is carrying sewage or other hazardous materials, it is unacceptable to allow leaks into the environment. Thus, a significant task for local, state and national governments around the world is to replace damaged pipelines with new ones.
However, as most pipes are underground, it is extremely expensive and time consuming to replace pipes. The earth around the damaged pipe must be excavated, and the damaged pipe must be removed from the ground. The new pipe segment must then be placed in the excavation site, joined and sealed to adjacent pipe segments, and then buried again. All of these tasks are very time consuming and require heavy machinery and many workers, thus making the replacement process very expensive.
As an alternative to excavating the damaged pipe, it is possible replace/repair the pipe from the inside out using a curable fabric liner. The liner, typically fiberglass or felt, is impregnated with a curable resin and then inserted or inverted (i.e. turned inside-out) into the damaged pipe. By using a fluid medium under pressure (e.g. gases or liquids, including air or water), the liner is pressed against the inner walls of the existing damaged pipe. Once the resin cures (due to a catalyst of heat, light, or chemical), the liner is rigid and the pressure source can be removed, leaving a new gas/liquid-tight inner wall of the damaged pipe.